CN104063007B

CN104063007B - Use the asynchronous time intertexture waveform generator of harmonic mixing

Info

Publication number: CN104063007B
Application number: CN201410190417.9A
Authority: CN
Inventors: J·E·卡尔森; J·马尔凯德
Original assignee: Tektronix Inc
Current assignee: Tektronix Inc
Priority date: 2013-03-21
Filing date: 2014-03-21
Publication date: 2018-09-21
Anticipated expiration: 2034-03-21
Also published as: JP6478215B2; CN104063007A; US20150077169A2; US20140285251A1; JP2014187693A; EP2782257A2; EP2782257A3; EP2782257B1; US9093955B2

Abstract

The present invention relates to a kind of asynchronous time intertexture waveform generators using harmonic mixing.Waveform generator includes the separator that digital input signals are divided into multiple separation signals, and each signal that detaches has the separation signal frequency bandwidth substantially similar with digital input signals frequency bandwidth.Separation signal is mixed with associated digital harmonic signal to generate multiple digital mixing signals, it is then converted into analog signal with the efficiently sampling rate different from least one digital order harmonic signal of harmonic mixer.Associated analog signal is mixed with associated simulation harmonic signal to generate mixed analog signal by multiple simulation harmonic mixers.Mixed analog signal is merged into the output signal of the output signal bandwidth with the bandwidth for being more than at least one of multiple DAC.

Description

Use the asynchronous time intertexture waveform generator of harmonic mixing

Cross reference to related applications

This application claims the profits of the U.S. Provisional Patent Application for the application number 61/803,970 submitted on March 21st, 2013 Benefit, entire contents are incorporated herein.

Technical field

This disclosure relates to generate the waveform generator and method of waveform.More specifically, this disclosure relates to using harmonic mixing High speed arbitrary waveform or function generator.

Background technology

Waveform generator（Such as, arbitrary waveform generator（AWG）Or arbitrary-function generator（AFG））Available bandwidth energy Enough digital analog converters that signal is generated by being used to according to digital waveform sequence（DAC）To limit.The available bandwidth of DAC It is limited by smaller in the analog bandwidth of DAC or the half of maximum sample rate.For using existing DAC limit generate compared with The routine techniques of high bandwidth output signal can be complicated and costliness system.

Effective higher DAC sample rates are can be utilized to implement for example, interweaving synchronization time.Multiple DAC are according to single The separation list entries that is deviated on time in the DAC sampling periods generates waveform.Analog signal is merged and reaches actually Multiplication（multiply）Sample rate.However, in wherein the analog bandwidth of DAC becomes the example of limiting factor, high band is needed Wide activity combiner（Such as, analog multiplexer or sampling and holding multiplexer）To realize higher bandwidth.

In terms of the conventional time-interleaved system of multiplexing makes multiplexer come by the sample rate similar with DAC bandwidth chahnels When（clock）, so that DAC comes transition and stabilization during multiplexer clock interval with the sufficient time.At these In conventional system, DAC and multiplexer synchronously timing, so that each DAC samples are gated by multiplexer （gate）And it then selects.Such limitation of DAC bandwidth limits DAC sample rates, and then limits multiplexer Clock rate.As a result, these conventional systems need multiple channels DAC to realize desired performance.

Since the quantity in the channels DAC increases, so the overall cost and complexity of system correspondingly increase.For example, each DAC needs individual memory and numeral input path and timing and makes the method for all DAC Channel Synchronous, this needs physics Upper large-scale and complicated multiplexing chip.The increased size and complexity for multiplexing chip also result in longer communication Path, and in terms of thus leading to parasitic capacitance, inductance, electromagnetic noise and the difficult design other than other challenges Increase.

In another technology, the sub-band of input signal is digitally down-converted to can be by compared with low sampling rate DAC's Frequency range.Larger input signal bandwidth is divided into the channels multiple low bandwidth DAC.It is converted into mould at the low bandwidth of DAC After quasi- signal, sub-band is digitally upconverted to corresponding original frequency range, and is merged into digital input signals It indicates.However, when conversion has the arbitrary input for the frequency content for being routed through the single channels DAC, because again Output after merging has the signal energy from the channels only one DAC and the noise energy from all channels DAC, so its Including intrinsic noise, this makes the whole signal-to-noise ratio of system（SNR）Degrade.

Therefore, this field will benefit from having the waveform of improved SNR to generate device and method.

Description of the drawings

Fig. 1 is the block diagram of the example waveform generator according to an embodiment of the invention using harmonic mixing.

Fig. 2 is the block diagram of another example waveform generator according to the embodiment using harmonic mixing.

Fig. 3 A, 3B, 4A, 4B, 5A, 5B and 6 are the various letters that the example waveform generator shown in Fig. 1 is generated Number illustrative spectral components.

Fig. 7 A, 7B, 8,9 and 10 are the circuit diagrams of the exemplary harmonic mixer of disclosed waveform generator.

Specific implementation mode

The present disclosure describes the sample rates and available bandwidth for improving analog output signal by using harmonic mixing Waveform generator DAC systems embodiment.

It can be the example of optional various filters in the various examples that Fig. 1, which is using harmonic mixing and some of which, The block diagram of property waveform generator 100.Waveform generator 100 includes the separator for being configured to receive digital input signals 104 102.Separator 102 is configured to digital input signals 104 being divided into multiple separation signals 106.Digital input signals 104 can It is any suitable Wave data sequence.

Each separation signal 106 has the separation signal frequency bandwidth substantially similar with frequency input signal bandwidth.Point Can be any kind of circuit that digital input signals 104 can be divided into multiple signals from device 102.For example, separation signal 106 can include any desired digital input stream with given sample rate, and include recording, store, and/or giving birth to At data sequence.

Separation signal 106 is input to and is configured to its associated separation signal 106 and associated digital harmonic signal It is digitally mixed to generate the digital harmonic mixer 108 of digital mixing signal 110.Each number harmonic mixer generates number Mixed frequency signal.As shown in fig. 1, digital harmonic signal can include the local oscillator that harmonic signal is applied to separation signal （LO）112.In some exemplary systems, digital LO can be digital controlled oscillator.

Digital harmonic mixer 108 is configured as any equipment for being mixed signal with multiple harmonic waves.Although Combined harmonic mixing describes multiplication and/or mixing, but as will be described in more detail, can will have make signal with Any equipment for the effect that multiple harmonic waves are multiplied is used as harmonic mixer.

In some instances, multiple harmonic waves can include zeroth order harmonic wave or DC components.For example, harmonic signal can be by Formula（1）Represented signal：

（1）Harmonic signal=

In formula（1）In, F₁Indicate an order harmonics, and t indicates the time.Thus, there is formula（1）Form signal With at DC and frequency F₁The harmonic wave at place.

Reversed phase signal harmonic wave can be by formula（2）Represented signal：

（2）Paraphase harmonic signal=

With by formula（1）Represented harmonic signal is similar, and paraphase harmonic signal has at DC and frequency F₁The harmonic wave at place. However, frequency F₁One order harmonics at place are relative to by formula（1）A similar order harmonics out-phase in represented harmonic signal 180 degree.

Referring again to Fig. 1, mixing frequency digital signal 110 is input to filter 114.Mixing frequency digital signal 110 can have The sample rate of maximum efficiently sampling rate more than DAC 122, and can include the half of the efficiently sampling rate more than DAC 122 Frequency bandwidth.Filter 114 can limit the bandwidth of mixing frequency digital signal, to prevent aliasing signal to be distorted.

Filter can include the net filtering generated to mixed frequency signal（net filtering）Symmetric low-pass filter （LPF）, the mixed frequency signal is with approximately half of frequency sound being substantially complementary with the frequency of an order harmonics of harmonic signal It answers.Higher than F₁Frequency response at/2 given offset and it is less than frequency F₁Frequency response at/2 given offset can add as 1.Although 1 is used as example, as desired, such as other values can be used for scale signal.Further, will show above Example is described as ideal situation.The filtering realized can have different responses, to consider nonideal component, calibration Deng.

Balanced-filter is shown in the numeric field 116 of waveform generator shown in Fig. 1, but it is in other examples It can alternatively or additionally be included in analog domain 118.Filtered mixing frequency digital signal 120 is input to associated Digital analog converter 122（DAC）.The sample rate of filtered mixing frequency digital signal 120 is downsampled to match the sampling of DAC Rate, in some instances, the DAC can merge with filter 114.Down-sampling can pass through extraction（decimate）After filtering The output sequence of mixing frequency digital signal 120 such as occurred by retaining the small number of sampling of output sequence.

Any one of separation, filtering, mixing, and/or down-sampling described above can be by any suitable numbers Circuit realizes, including but not limited to, digital signal processor（DSP）, microprocessor, programmable logic device, general procedure Device or other processing systems with peripheral equipment appropriate include as expected the complete set to complete discrete component At.

Each DAC 122 is configured to filtered mixing frequency digital signal 120 being converted into analog signal 124.DAC 122 is It is configured to convert digital signals into any kind of circuit of analog signal.As needed, each DAC 122 can include putting Big device, filter, attenuator and other numbers or analog circuit, with before digital signal is converted into analog signal or Amplify, filter, decay or handle in other ways signal later.

DAC 122 is configured as operating with efficiently sampling rate.It, will in example waveform generator shown in Fig. 1 DAC 122 is shown as single DAC, but in other examples, and each DAC may include multiple come what is operated with lower sample rate The DAC of intertexture, to realize higher efficiently sampling rate.

DAC 122（Or the DAC of multiple intertextures）Efficiently sampling rate and at least one associated digital harmonic mixing One order harmonic signal of device 108 is different.An order harmonics and at least one DAC at least one digital harmonic signal 122 efficiently sampling rate is different.For example, an order harmonics F of harmonic signal₁It can be 20 GHz, and the sample rate of DAC 122 Can be 25 GS/s.Thus, an order harmonics F₁It is different from the efficiently sampling rate of DAC 122.

In some instances, an order harmonics of digital harmonic signal need not be the integer of the efficiently sampling rate of DAC 122 Multiple or approximate number.An order harmonics with 108 associated harmonic signal of digital harmonic mixer are not the efficiently sampling rates of DAC 122 Integer multiple or approximate number.

In some instances, an order harmonics of harmonic signal are at the efficiently sampling rate of DAC 122 with DAC's 122 Between the half of efficiently sampling rate.This quefrencys of one order harmonics allow on an order harmonics and/or under upper frequency point Amount is down-converted to the half of the sample rate less than DAC 122.Thus, such frequency component can effectively be converted by DAC 122 For analog signal 124.

Each frequency band of separation input signal passes through all paths.When to be combined to processing single defeated in more than one channel When entering signal, each channel or path substantially receive the whole bandwidth of digital input signals.Since digital input signals pass through All DAC are sent, so improve SNR.

Analog signal 124 is input to optional filter, such as, shown in the example waveform generator 100 of Fig. 1 Reconstruction filter 126.Reconstruction filter 126 is configured to be filtered the analog signal 124 from DAC 122, and substantially Eliminate the DAC image frequency components in signal 124.In some alternative examples, reconstruction filter can be DAC and/or A part for frequency mixer.

Filtered analog signal 128 is input to multiple associated harmonic wave Analogue mixers 130.Each separation is believed Number channel, there are a frequency mixers 130.Harmonic wave Analogue mixer 130 is configured to the pass in filtered analog signal 128 One of connection is mixed with simulation harmonic signal, to generate multiple mixed analog signals 134.In some instances, it simulates humorous Wave signal and corresponding digital harmonic signal are substantially similar in terms of frequency and phase.The harmonic signal of harmonic wave Analogue mixer It can include the local oscillator that harmonic signal is applied to filtered analog signal 128（LO）132.As retouched more fully below It states, the LO 132 of simulation harmonic signal can be made synchronous with the number LO 112 of harmonic signal.

Although digital harmonic signal and simulation harmonic signal are digital and analog signaling respectively, for their ratio because Son can be mutually the same or similar.Output signal from simulation harmonic mixer is known as mixed frequency signal 134 again.

Mixed frequency signal 134 it will be input to again and be configured to be mixed multiple again（Or mixing）Analog signal 134 merges At the list of the output signal 138 of the output signal bandwidth with the bandwidth more than at least one of multiple digital analog converters A combiner 136.Analog output signal 138 from combiner 136 is the digital input signals for being applied in separator 102 104 reconstruction.

The some form of synchronization of harmonic signal 112,132 is used.For example, the harmonic lock of harmonic signal can will be simulated It is fixed to arrive and the relevant clocks of DAC.Number and Analogue mixer frequency can be present in an analogue form in the channels DAC but With the relevant harmonic wave compared with low-speed clock of digit data stream.In other examples, digital harmonic signal or coherent signal are also by DAC It converts, and can be used in analog domain, to be synchronized with simulation LO signals.In still another example, with outer tone energy Enough it is added to one or more of mixing frequency digital signal.Using the 9/16 of 20 GHz, 11.25 GHz or 20 GHz one Order harmonics can be added to mixing frequency digital signal.Because the tone added can be set as by one or more optional The bandwidth that digital filter is established（It is about 9 GHz dependent on intermediate zone）Except, so tone can be to from combiner institute Signal after the reconstruction of output has substantially insignificant influence.However, tone can be small for 25 GS/s sample rates It is less than 12.5 GHz in Nyquist frequency, this means that tone can be by using institute before being filtered to analog frequency mixing signal Analog frequency mixing signal is stated to acquire.Regardless of used simultaneous techniques, digital harmonic signal and simulation harmonic wave letter are all maintained Phase and frequency relationship between number.

Fig. 2 is the waveform generator with the input signal 202 for being divided into two channels DAC 206,208 by separator 204 200 example.Example shown in Fig. 2 includes the specific example for various components and for signal frequency, sample rate etc. Value.Digital input signals 202 are the random waveform sequences of the sample rate with 50 GS/s.Digital input signals 202 are limited to by band 18 GHz, to prevent the mixed components from various harmonic signals from extending across neighbouring harmonic frequency.The sequence is replicated, and Each path is inserted into the sample rate or 100 GS/s of 2 × digital input signals by separator 204 in.

Then the paraphase between two paths 206,208 is used by digital mixer 210,211（180 degree phase shift）Clock comes The signal of duplication is digitally mixed with the zero and first order harmonic wave 212,213 of 20.3125 GHz clocks.Then, mixing frequency digital Signal 214 by symmetrically low-pass filtering 216 and be drawn into the input for being each associated DAC 218 sample rate 25 GS/s sample rates.If desired, digital harmonic mixing and filter step can merge with filtering extraction.DAC is exported again It is filtered using reconstruction filter 220, to remove the image signal caused by DAC itself, and with 10.15625 GHz（That is, the half of harmonic signal bandwidth）Frequency components amplitude symmetrically from Analogue mixer output net response.

Then, the paraphase between two paths is reused by Analogue mixer 224（180 degree phase shift）Clock is being simulated The identical zero and first order harmonic wave of filtered analog signal 222 and 20.3125GHz digital dock 212 is mixed in domain Frequently.Two paths are summed and filter at combiner, to remove the content on 20.3125 GHz.Shown in fig. 2 In exemplary arbitrary waveform generator 200, the LO 212,213 and simulation harmonic mixer of digital harmonic mixer 210,211 224 LO 226 can use 13 order harmonics of frequency dividing sampling clock.（25 GHz/16=1.5625 GHz, 13 * 1.5625 = 20.3125 GHz）.

Fig. 3 A-6 are the examples of the spectrum component of the various signals in waveform generator system shown in Fig. 2.Fig. 3 A show Go out as digital input signals and thus be Fig. 2 separation signal frequency spectrum frequency spectrum 300.Use formula（1）Defined in Harmonic signal above example, as represented by frequency spectrum 300, the DC components of harmonic mixer make separation signal pass through.So And also by the frequency spectrum 300 and frequency F in input signal₁One order harmonics at place are mixed.As a result the frequency spectrum 302 of gained is this The product of kind mixing.Thus, digital mixing signal includes the component of frequency spectrum 300 and frequency spectrum 302.Herein and in other attached drawings In, spectrum component be illustrated as individually and be overlapped, however, actual frequency spectrum by be frequency spectrum 300 and 302 merging.

With reference to Fig. 3 B, since the DC harmonic waves of digital input signals and the paraphase LO signals of digital harmonic mixer being mixed Frequently, so the component of 310 analogously represented paraphase digital mixing signal of frequency spectrum.312 analogously represented paraphase LO of frequency spectrum and frequency spectrum 310 mixed product.As described above, an order harmonics of the paraphase LO signals of digital harmonic mixer are from LO signals 212 Order harmonics phase shift 180 degree.180 degree phase shift in paraphase number harmonic signal induces the 180 degree phase shift in frequency spectrum 312. In figure 3b, 180 degree difference is illustrated as dotted line.

Fig. 4 A and 4B indicate the frequency spectrum of filtered digital mixing signal.In this example, it is public can be happened at institute for filtering In the number and/or analog domain of the waveform generator system and method opened.It is approached for example, digital mixing signal can utilize to have The symmetrical LPF of number of the cutoff frequency of the half of the efficiently sampling rate of DAC is filtered.In some instances, filtering can be pair The function of the Inherent filtration of DAC, the digital filter answered etc..

In some instances, the single order with the LO signals of digital mixer can result in the net filtering of digital mixing signal Approximately half of frequency response being substantially complementary of the frequency of harmonic wave.Higher than frequency F₁Frequency response at/2 given offset and Less than frequency F₁Frequency response at/2 given offset can add as 1.Although having used 1 in this example, as desired, Can such as other values be used for scale signal.Further, above example is described as ideal situation, and added Filtering can be used to consider nonideal component, calibration etc..In exemplary system, decimation filter, balanced-filter, with And calibration filter is also used to compensate for the nonideal response in analog domain.

In the particular example of frequency response, 20.3125 GHz F described above are used₁, frequency F₁/ 2 are 10.15625 GHz.From DC to 9.12625 GHz, frequency response is 1.The GHz from 9.15265 to 11.15625, frequency response from 1 to linearly change be 0, to 10.15625 GHz at by 1/2.It has been illustrated in figures 4A and 4 B the frequency spectrum point obtained by result Amount.Fig. 4 A show including by 400 illustrated frequency spectrums 300 lower frequency part and by 402 illustrated frequency spectrum 302 of frequency spectrum Lower frequency part filtered mixed analog signal.Due to digital mixing, so frequency spectrum 402 is although anti-in frequency Turn, but also includes the frequency component of the higher sub-band of frequency spectrum 300.Similarly, the spectrum component 410 of Fig. 4 B and 412 and Fig. 3 A Frequency spectrum 310 and 312 lower frequency components it is corresponding.The 180 degree phase relation of frequency spectrum 312 is saved in frequency spectrum 412.

Therefore, by harmonic mixing, although the span of sub-band will be more than with the associated Nyquist bandwidths of DAC, Two sub-bands of digital input signals are also translated into analog signal.Each mixed frequency signal（No matter simulation, digital, filter After wave etc.）The component of each sub-band including digital input signals, the low frequency of frequency spectrum 300 shown in such as Fig. 4 A and 4B Sub-band and high-frequency subbands.

For example, the sub-band of digital input signals by frequency displacement in the bandwidth in base band sub-band.In some instances, Each sub-band of digital input signals is by frequency displacement in the bandwidth in single sub-band.However, dependent on harmonic signal and The quantity of sub-band, each sub-band can be not present in each mixed frequency signal.

Fig. 5 A and 5B indicate the frequency spectrum for being input into the signal after the mixing again of combiner.As described above, mould Rahmonic signal and digital harmonic signal can have substantially similar frequency and phase.Therefore, by the frequency spectrum and DC of Fig. 4 A Component and First-Order Mode rahmonic signal are mixed.Frequency spectrum 500 and 502 indicate by the frequency spectrum 400 of Fig. 4 A and 402 with DC components into The frequency spectrum of row mixing gained.Frequency spectrum 504 indicates the result for being mixed frequency spectrum 400 with an order harmonics.Frequency spectrum 506 and 508 tables Show and is mixed the frequency spectrum 402 of Fig. 4 A with an order harmonics.

Similarly, Fig. 5 B indicate the frequency spectrum of the signal after the mixing again for paraphase harmonic signal.Frequency spectrum 510 and 512 DC components are mixed by expression with the frequency spectrum of Fig. 4 B.Frequency spectrum 514 indicates to simulate paraphase into the order harmonics and figure of harmonic signal The frequency spectrum 410 of 4B is mixed.Particularly, since the order harmonics that harmonic signal is simulated in paraphase have opposite 180 degree phase shift, So the frequency spectrum 514 obtained by result also has 180 degree phase shift, represented by dotted line.

The order harmonics that the frequency spectrum 412 of Fig. 4 B is also simulated to harmonic signal with paraphase are mixed；However, frequency spectrum 412 is Phase shift through being induced with 180 degree.Thus, additional 180 degree phase shift leads to effective 0 degree of phase shift, by frequency spectrum 516 and 518 Represented by solid line.

Fig. 6 shows the frequency spectrum 600 from the digital input signals after the reconstruction that combiner shown in Fig. 1 is exported.Frequently Spectrum 604 and 606 indicates to form the component sub-band of frequency spectrum 600.Frequency spectrum 602 indicates that basis is mixed about described in Fig. 5 A and 5B Additional side.In this example, frequency spectrum 602 is filtered；However, in other examples, sub-band can extend beyond single order Harmonic frequency F₁.In this case, because frequency spectrum 602 is generated from lower frequency sub-bands, the conjunction of cancellation can be passed through And to eliminate it.

Due to the relative phasing of the component of the signal after being mixed again, so the sub-band in its original frequency range is mutually grown Ground merges, and the sub-band except its original frequency range is coordinated and destructively merged surely.With reference to Fig. 5 A, 5B and 6, work as quilt When merging, frequency spectrum 500 and 510 constructively merges, this leads to frequency spectrum 604.Cancellation due to frequency spectrum out-phase 180 degree of frequency spectrum 502 and 512 Ground merges.Thus, the frequency spectrum stayed in base band sub-band is original sub-band.

Similarly, for from about F₁/ 2 arrive F₁Sub-band for, frequency spectrum 506 and 516 is constructively merged into frequency spectrum 606, And frequency spectrum 504 and 514 destructively merges.Frequency spectrum 508 and 518 is constructively merged into frequency spectrum 602；However, since frequency spectrum 602 exceeds Desired input frequency range（In this example, about it is less than frequency F₁）, so the frequency spectrum 602 can be filtered.

Such as illustrated by frequency spectrum 604 and 606, transition is happened at as filtering above by reference to described in Fig. 4 A and 4B As a result frequency F₁Around/2.The slope of frequency spectrum 604 and frequency spectrum 606 is complementary.Thus, when the frequency point of frequency spectrum 604 and 606 When amount is merged, the part obtained by the result of frequency spectrum 600 is substantially matched to original frequency spectrum.

Therefore, by being mixed digital input signals with various harmonic signals, make the sub-band of digital input signals Pass through the lower bandwidth of DAC.Although mixed frequency signal includes the sub-band of overlapping, phase is determined due to harmonic signal, so working as When being merged as described above, sub-band constructively and destructively merges, to create the substantially accurate of digital input signals True simulation is rebuild.

In some instances, analog- and digital- harmonic signal frequency and phase alignment each other.Alignment simulation and harmonic signal Frequency and phase a kind of mode be selected as in the channels DAC being present in analog domain but also with digital harmonic signal The mixing frequencies of the relevant harmonic wave compared with low-speed clock.In other examples, the individual channels DAC are served as and simulation harmonic mixing The reference frequency that the mixing frequencies of device are multiplied.It is described above it is more exemplary in, simulation harmonic mixer is all logical Pass through DC harmonic signals on road.Alternatively, digital input signals can be divided into frequency band, and each frequency band with it is appropriate Harmonic signal is mixed to be multiplied.Then, digital band is reconsolidated before being converted into analog signal.For each frequency band Speech, only one clock harmonic generate the mixed product in the low-pass filter bandwidth in the channels DAC.Handle only having needed for DC inputs Digital harmonic mixer be used for low input frequency band, DC input is mixed with zeroth order clock harmonic（That is, be multiplied by 1 or Directly pass through in the case of not needing frequency mixer actually）.

In another replacement, Analogue mixer can be by making standard mixer topology be adapted for carrying out including DC components Harmonic mixing on all channels makes DC harmonic signals pass through.

Fig. 7 A and 7B illustrate the harmonic wave that can indicate any one or more of harmonic mixer discussed above The example of frequency mixer.Fig. 7 A illustrate the time-interleaved switch in 2 tunnels.Fig. 7 B illustrate the time-interleaved switch in the roads N.

In these embodiments, switch 780 and/or 781 is configured as output signal 782.When using 2 way switch 780, Input signal 784 or 786 arrives output 782 in response to control signal 788.When using N way switch 781, believe in response to control Numbers 788 and by input signal 784,786 until n-th input 787 is switched to output 782.For example, switch 781 can three be thrown Switch, four throw switches etc. make input signal 784,786 be spent at output 782 until n-th input 787 until N throw switches The 1/N of its time.Due to being added to further path and sub-band, so the harmonic wave of harmonic signal can suitably be determined Phase.In some embodiments, the relative phase shift of harmonic signal can by divided by sub-band quantity a period time shift And it is spaced in phase.

Since compared with the whole clock cycle, pulse becomes shorter, so harmonic content becomes more rich.For example, for For two-way or three-way switch, zeroth order harmonic wave has been used（DC）With an order harmonics.For four tunnels or five way switch, it can make With zeroth order harmonic wave, an order harmonics and the second harmonic.For six tunnels or seven way switch, zeroth order harmonic wave, single order can be used humorous Wave, the second harmonic and three order harmonics.As N increases, pulse becomes narrower, to generate more rich harmonic content.Control letter Numbers 788 can be the signal of the basic frequency or other suitable harmonic frequencies with an order harmonics described above.

Input signal 784,786 passes through outgoing route 782 until all frequency bands of n-th input 787.

For example, referring to switch 780, control signal 788 can be the square wave with 20.3125 GHz basic frequencies.As Switching as a result, output 782 receives input signal 784 or 786 during a half period of control signal, and opposite one Other input signals are received during half period.In fact, for example, output 782 is that input signal 784 or 786 is multiplied by 20.3125GHz locating the square wave vibrated between zero and one.Such square wave can be by formula（4）To indicate.

（4）

Formula（4）It is the Taylor series expansion of such square wave.List DC and the first two harmonic wave.Herein, F₁It is 20.3125GHz.Although the magnitude of component is different, formula（1）With（4）Including similar harmonic wave.Input 786 and 784 phases of input It is similar；However, relative to input 784, input signal 784 or 786 be routed to output 782 by period be reversed. The effect again be similar to make input signal 784 or 786 with by formula（5）Defined square wave is multiplied.

（5）

Similar to formula（4）, formula（5）With above formula（2）Described in harmonic signal it is similar.Thus, switch The multiplication effect of 780 switching is substantially similar to the signal described above that will detach and is mixed with harmonic signal.In addition, In this example, switch serves as both combiner and harmonic mixer.However, in other embodiments, switch 780 can be Single-pole single-throw switch (SPST), and serve as single harmonic mixer.

Although the relative magnitude of DC components and an order harmonics is different, such imbalance can be by path appropriate Compensating filter corrects.For example, frequency F described above₁/ 2 and frequency F₁Between sub-band can have combiner in Reconsolidate during the gains different from base band sub-band that are applied.

In addition, above formula（4）And formula（5）Also list three order harmonics.In some embodiments, three order harmonics can To be desired.However, if it is not, the effect of this rahmonic can be compensated using filtering appropriate.For example, can be right Input signal is filtered to remove frequency F₁On frequency component.Thus, such frequency component will be not present without with 3* F₁The frequency at place is mixed.In addition, being filtered and can remove before DAC analog signal may be influenced because of aliasing originally Any higher order frequency component.

In the case where intertexture error occurs because of mismatch, can carry out hardware adjustment for clock amplitude and phase into Row mixing.Then, the adjustment can be calibrated so that intertexture mismatch is spuious（spur）It minimizes.Alternatively or divided by Except upper method, hardware mismatches can be characterized, and linear time-varying correcting filter can be used to eliminate interweave it is miscellaneous It dissipates.

Further, in some cases, switch always may not be operated ideally.For example, the switch of error may be It is taken more time than other direction on one direction, so as to cause crooked duty ratio.Digital harmonic mixer can match It is set to and is likely to be present in simulation harmonic signal by carrying out subtle adjustment to the amplitude or phase of simulating harmonic signal to compensate Phase or range error.

Fig. 8 is the example of another harmonic mixer.Switching circuit 800 be configured to respond to control signal 806 and incite somebody to action Two input signals 808 and 810 alternatively switch to output 802 and 804.Again, control signal 806 can be square wave or make Obtain other similar signals that the switch of switching circuit 800 can switch over.It is defeated during a half period of control signal 806 Enter signal 808 and is switched to output 802, and input signal 810 is switched to output 804.During another half period, input letter Numbers 808 are switched to output 804, and input signal 810 is switched to output 802.

In some embodiments, the reversing and the version after scaling that input signal 810 can be input signal 808.More than Described switch and such input the result is that the DC of the level described in the switch 780 above with respect to Fig. 7 A and other The rebalancing of harmonic wave.For example, the score that input signal 810 can be input signal 808 reverses version.As utilization Fig. 7 A's Switch 880 is come the replacement that switches between 1 and 0, for example, effective export of output 802 and 804 can be in 1 He Between switch.Thus, amplitude and DC level can be as expected adjusted to create the desired balance between harmonic wave.

Fig. 9 illustrates the alternative example of harmonic mixer.Harmonic mixer 970 includes separator 972, frequency mixer 975 and combiner 977.Separator 972 is configured as input signal 971 being divided into signal 973 and 974.Signal 974 is defeated Enter to combiner 977.Since signal 974 is not mixed with another signal, thus signal 974 serve as it is described above humorous The DC components of wave mixing device.

Signal 973 is input to frequency mixer 975.Signal 976 is mixed with signal 973.In some embodiments, believe Numbers 976 can be single harmonic wave, all frequency F as described above₁.If additional harmonic wave is desired, can Additional frequency mixer is provided, and merges corresponding output in combiner 977.

In another embodiment, signal 976 can include multiple harmonic waves.As long as the bandwidth of the port of frequency mixer 975 is suitable Answer desired frequency range, it will be able to use single frequency mixer 975.However, because the DC of harmonic signal described above Component is transmitted to combiner 977 by different paths, so the port for receiving the frequency mixer of signal 973 and 976 does not need It works to DC.Therefore, it is possible to use the frequency mixer of wide type.Once incorporating 979 He of signal in combiner 977 974, output signal 978 can be substantially similar with mixed frequency signal described above.

In some embodiments, separator 972 can but need not symmetrically detach input signal 971.For example, defeated Go out the separator of signal 974 side have at the filter cutoff frequency described above or on bandwidth.Output letter There is frequency range centered on the harmonic wave of signal 976 and filtering described above to cut for the side of numbers 973 separator 972 The only bandwidth of twice or more of frequency times.In other words, the frequency response of separator 972 need not be equal to each path , and can as expected adjust.

For example, Figure 10 is the circuit diagram of exemplary mixer topologies 1000, by making diode loop mixer be suitable for The simulation harmonic mixer for two-way interlacing system is realized to execute the harmonic mixing with DC components.In this example, can The harmonic signal 1002 of such as frequency mixer clock etc is input to diode ring 1004 by transformer 1006.It can will input Signal 1008,1010 is applied to input 1012 and 1014.Therefore, harmonic signal is depended on, it can be by input signal alternatively Be switched to output 1016, transformer 1006 centre cap.For example, when transformer bottom is harmonic wave just and when top is negative Signal makes right diode current flow, or when the reversion of the polarity of transformer, makes left diode current flow.In this manner, alternately will Two input signals 1008,1010 are routed to the output in two opposite half of harmonic period.Note that in this example, two Pole pipe ring mixer provides the combination function of two frequency mixers and combiner.

In some embodiments, the sub-band in two paths and two overlappings is realized.However, as the above mentioned, Any amount of path and sub-band can be used.In such embodiments, the quantity of used harmonic wave can be equal to downward One and half of the number of sub-bands of rounding, wherein including as zeroth order harmonic wave using DC.For example, for three sub-bands For, only two harmonic waves can be used.More than use frequency range is as an example, an order harmonics can will be than frequency F₁High Frequency shift is to base band sub-band.One order harmonics of harmonic signal can determine phase using 120 degree of relative phase shifts.

Therefore, when during the merging when sub-band in combiner 58 in suitable frequency range, sub-band spectra By phase shift having the same, such as 0 degree of relative phase shift.Conversely, three components of the sub-band in incorrect frequency range will 120 degree are offset from one another in phase.As a result the frequency spectrum of gained will destructively merge to eliminate incorrect sub-band.Due to addition Further path and sub-band, the harmonic wave of harmonic signal suitably can be determined phase.In some embodiments, harmonic signal Relative phase shift can by divided by sub-band quantity a period time shift by be spaced in phase.

In addition, although digital filtering, mixing and merging are described as discrete operations, it can be by this generic operation Merge, to be incorporated into other functions medium.In addition, ideal component is assumed due to described above, so can be as suitably will Additional compensation is introduced into such processing, to be corrected to nonideal component.

Another embodiment includes the computer-readable code embodied on computer-readable medium, when the code is transported When row, computer is made to execute any one of operations described above.As it is used herein, computer is can to run Any equipment of code.

Microprocessor, programmable logic device, multicomputer system, digital signal processor, personal computer etc. are all The example of such computer.In some embodiments, computer-readable medium can be configured as depositing in a manner of non-provisional Store up the visible computer readable medium of computer-readable code.

It will be appreciated that the change of the system and method and other feature and function for generating waveform disclosed above Shape or its replacement may desirably be merged into many other different systems, method or application.It is also possible to by this field Technical staff subsequently makes and wherein various can not currently predict or unforeseen replacement, modification, deformation or improve.

Claims

1. a kind of waveform generator, including：

Separator is configured to receive the digital input signals with frequency input signal bandwidth, and being configured to will be described Digital input signals are divided into multiple separation signals, and each of described separation signal has and the frequency input signal bandwidth class As detach signal frequency bandwidth；

Multiple number harmonic mixers, be configured to detach associated one in signal with associated number harmonic signal into Row digital mixing, to generate multiple digital mixing signals；

Multiple digital analog converters, each of the multiple digital analog converter are configured to the multiple number is mixed Associated digital mixing signal in frequency signal is converted to analog signal, each of described digital analog converter have with extremely The different efficiently sampling rate of an order harmonic signal of a digital harmonic mixer less；

Multiple simulation harmonic mixers are configured to carry out associated one in the analog signal with simulation harmonic signal Mixing, to generate multiple mixed analog signals；And

Combiner is configured to the multiple mixed analog signal being merged into more than the multiple digital analog converter At least one of bandwidth output signal bandwidth output signal.

2. waveform generator as described in claim 1, the single order of associated digital harmonic mixer described in wherein at least one Harmonic signal is not the integer multiple or approximate number of the efficiently sampling rate of at least one digital analog converter.

3. waveform generator as described in claim 1, wherein with the associated at least one harmonic signal of digital harmonic mixer An order harmonics be in the efficiently sampling rate of at least one digital analog converter and at least one digital analog converter Efficiently sampling rate half between.

4. waveform generator as described in claim 1, wherein bandwidth of the multiple digital mixing signal in single sub-band Interior at least two sub-bands for including the digital input signals.

5. waveform generator as claimed in claim 4, wherein the single sub-band is base band sub-band.

6. waveform generator as claimed in claim 4, wherein bandwidth of each digital mixing signal in the single sub-band The interior each sub-band for including the digital input signals.

7. waveform generator as described in claim 1 further comprises multiple symmetrical digital filters, the multiple symmetrical Digital filter be configured to before digital mixing signal is converted into analog signal to the multiple digital mixing signal Symmetrically filter.

8. waveform generator as described in claim 1 turns wherein the simulation harmonic mixer has with the digital simulation The different order harmonics of the efficiently sampling rate of parallel operation.

9. waveform generator as claimed in claim 3 a, wherein order harmonics of the number harmonic mixer and the simulation One order harmonics of harmonic mixer are similar.

10. a kind of method generating waveform, including：

Digital input signals with frequency input signal bandwidth are divided into each of multiple separation signals, the separation signal With the separation signal frequency bandwidth similar with the frequency input signal bandwidth；

Each of described separation signal is digitally mixed with associated digital harmonic signal with efficiently sampling rate, it is more to generate A digital mixing signal；

With the efficiently sampling rate different from an at least one associated digital order harmonic signal of harmonic mixing by the multiple number Word mixed frequency signal is converted to multiple analog signals；

Each of described analog signal is mixed with associated simulation harmonic signal, is believed with generating multiple mixed analogs Number；And

The multiple mixed analog signal is merged into more than band at least one in the multiple digital analog converter The output signal of wide output signal bandwidth.

11. method as claimed in claim 10, wherein the single order harmonic signal is not the multiple digital mixing signal quilt Be converted to the integer multiple or approximate number of effective conversion sample rate of the multiple analog signal.

12. method as claimed in claim 10, wherein the single order harmonic signal is in the multiple digital mixing signal quilt It is converted between effective conversion sample rate of the multiple analog signal and the half of effective conversion sample rate.

13. method as claimed in claim 10, wherein the multiple digital mixing signal wraps in the bandwidth of single sub-band Include at least two sub-bands of the digital input signals.

14. method as claimed in claim 13, wherein the single sub-band is base band sub-band.

15. method as claimed in claim 13, wherein each digital mixing signal wraps in the bandwidth of the single sub-band Include each sub-band of the digital input signals.

16. method as claimed in claim 12 a, wherein order harmonics of the number harmonic signal are believed with the simulation harmonic wave Number an order harmonics it is similar.

17. method as claimed in claim 12, it is right before digital mixing signal is converted to analog signal to further comprise The digital mixing signal symmetrically filters.